Sensitivity and Uncertainty Analysis of the keff for VHTR fuel

Abstract

For the uncertainty and sensitivity analysis of PMR200 designed as a VHTR in KAERI, MUSAD was implemented based on the deterministic method in the connection with DeCART/CAPP code system. The sensitivity of the multiplication factor was derived using the classical perturbation theory and the sensitivity coefficients for the individual cross sections were obtained by the adjoint method within the framework of the transport equation. Then, the uncertainty of the multiplication factor was calculated from the product of the covariance matrix and the sensitivity. For the verification calculation of the implemented code, the uncertainty analysis on GODIVA benchmark and PMR200 pin cell problem were carried out and the results were compared with the reference codes, TSUNAMI and McCARD. As a result, they are in a good agreement except the uncertainty by the scattering cross section which was calculated using the different scattering moment.